Magpie Goose (Anseranas semipalmata) Fact Sheet: Diet & Feeding

Herbivorous

(Frith and Davies 1961, and as noted)

• Seeds (Marchant and Higgins 1990; Carboneras and Kirwan 2017)
• Blades of grasses (Carboneras and Kirwan 2017)
  • Marsh grasses and land grasses (Frith and Davies 1961)
• Corms of Elocharis dulcis (water chestnut) (Traill and Brook 2011)
• Invertebrates
  • Found in stomachs of goslings (Frith and Davies 1961; Frith 1967)
  • Taken accidentally by adults (Frith 1967)
• For detailed summary, see Marchant and Higgins (1990)

Age/sex differences

• Large, socially dominant male birds take larger corms (Whitehead and Tschirner 1992; Carboneras and Kirwan 2017)
  • May have ability to dig deeper, to detect larger corms, or to feed in less disturbed sites
• Females and juveniles may ingest more, smaller corms (Whitehead and Tschirner 1992; Carboneras and Kirwan 2017)
  • Likely benefit from male’s ability to uproot plants and defend feeding territory

Finding food

• Strip seeds from grass heads with bill (Frith and Davies 1961)
  • Bend down tall grasses with feet
• Filter food from mud (Davies 1963; Carboneras and Kirwan 2017)
  • Draw water and mud into mouth
  • Use tongue to press mud through bill lamellae (comb-like ridges used for straining)
  • Feed in water up to 0.6 m (2 ft) deep (Frith 1967)
• Dig up corms and rhizomes using hooked bill (Frith and Davies 1961; Carboneras and Kirwan 2017)
  • Dig up from underwater, exposed soft mud, or dry ground
  • Scoop with bill, as head is extended and pulled back toward body (Davies 1963)
  • Frequently dig more than 20 cm (8 in) deep and turn over large expanses of mud (Whitehead and Tschirner 1991a)
    • At times, move far from water (Frith 1967)

Social interactions

• Feed as family groups during breeding season (Marchant and Higgins 1990)
• Feed as large flocks during non-breeding season (Marchant and Higgins 1990)

Seasonal changes in diet

• Year-round
  • Eat grass blades (Frith and Davies 1961)
• Wet season
  • Seeds of grasses important in diet (Frith and Davies 1961; Dawson et al. 2000)
  • After early rains, feed on new growth of grasses and annuals (Whitehead and Saalfeld 2000)
• Dry season
  • Aggregate in marshes to feed on energy-dense corms of the water chestnut sedge (Eleocharis dulchis) (Frith 1967; Dawson et al. 2000)
    • Other food items not available
  • Feed along marsh edges, following water edge as it recedes (Frith 1967)
  • Depart from corm-rich feeding sites as ground hardens (Dawson et al. 2000; Whitehead and Saalfeld 2000, and as noted)
    • Digging for corms becomes more difficult
      • Geese switch to a diet of mature grasses (and some corms); feed on margins of floodplain (Peter Bayliss, personal communication, 2018)
        • Grasses have little nutritional value
        • Body condition declines
      • May leave to seek out wetter locations (Wilson 1997)
  • Later in the dry season (October-December), food may be difficult for Magpie Geese to find (Frith and Davies 1961)
    • Body mass decreases

Drinking

• Drink to cool down (Davies 1963)
• Often drink while seated (Davies 1963)

Digestion and scat

• Digestive anatomy similar to geese and other waterfowl (Dawson et al. 2000)
  • Fiber digested anterior to hindgut
    • Fermentation of plant material limited to the caeca, rectum, and cloaca

Magpie Geese forage in water for submerged vegetation and the corms of water chestnuts.

Magpie Geese commonly submerge their head, neck, and forebody, but do not dive.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.